[AT] Hydraulic flow question?

[Carl Gogol]

Thomas & Dennis
All good points.  I think that I was confused regarding the inlet and outlet because the valve (Husco) has pressure and tank ports that are unlabeled SAE 12 and SAE 16.  My confusion was/is that I assumed that SAE 16 port (the larger) was return to tank.  Thomas, you pointing out the need for the relief valve to be adjacent to the outlet makes sense to me.  What doesn't make sense to me is the return port being smaller than the high pressure in port.
Of course I do not have fittings on hand to make this a quick swap to try things.  I have a pressure gauge and have previously plumbed ports to make measurements as necessary.  Stay tuned, it will probably take a week to get the needed SAE fittings before I can finish.  
And thanks James for cajoling me to describe the circuit.  I think the fix is clear.
Carl
Manlius, NY

-----Original Message-----
From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of Thomas Martin
Sent: Thursday, October 10, 2019 10:36 PM
To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
Subject: Re: [AT] Hydraulic flow question?

That's the problem, the relief valve should adjacent to the return to the tank!
Otherwise the pressure relief valve is not protecting the actuation circuits.
I'm surprised the valve housing is not marked with P for pressure & T for tank.

Tom
> On 11 October 2019 at 12:00 Carl Gogol <cgogol1971 at gmail.com> wrote:
> 
> 
> James,
> The circuit is simple.  It is a three spool mono block open center valve.
> It is good for about 20 GPM and the tractor's pump is about 12 GPM> 
> High pressure oil from pump is first going through the valve's 
> pressure relief valve;
> 1-  next in line is the motor control spool, a 4-way with detents with 
> oil returning to its companion port.
> 2- Oil then flows to a 4-way port to ram #1. power extend, gravity 
> return both on one of the spool's ports.  I'm not sure it is needed 
> but this spool's companion port is never-the less connected to the return flow line.
> I used it on a similar mower and don't remember if this connection was 
> required.  Don't see how it hurts even if it is unnecessary.
> 3- second ram is identical to #2 above but downstream from #2.
> 4- Finally oil is returned to the reservoir Carl Manlius, NY
> 
> -----Original Message-----
> From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of James 
> Peck
> Sent: Thursday, October 10, 2019 11:18 AM
> To: Antique Tractor Email Discussion Group 
> <at at lists.antique-tractor.com>
> Subject: Re: [AT] Hydraulic flow question?
> 
> I believe some hydraulic valves use orifices to limit spool speed. Can 
> you sketch the circuit for us?
> 
> [Carl Gogol] I just finished replacing a triple valve on my 
> International
> 140 that controls a side mount Alamo (triumph) sickle bar mower.  I 
> did it because I had the valve and the motor control on the "new" 
> valve would reverse the
> motor where the original would not.  This is handy when the mower jams.   
> The problem I created is the two controls for the hydraulic rams for 
> positioning the cutter bar are connected with ¼" hoses but the valve's 
> ports are all ½', -- but so were the original valve's.
> Problem - just moving one of the control's levers for a ram will stall 
> the tractor if opened all or most of the way.
> One solution - Limit the movement of the ram spools in some manner 
> like using a spacer to limit spool travel.
> Question - Is there a more hydraulicy correct way -  the original 
> valve did not suffer this issue.  BTW- system is open center.
> Carl
> Manlius, NY
> 
> Humm- I wonder if the valve's high pressure bypass is not working or 
> set too high?
> 
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